Plastic cork



Aug. 30, 1960 v. ALVEAR PLASTIC CORK Filed Sept. 4, 1958 a w M Hill V/CTOA AL I/[AR IN V EN TOR.

- ATTOEY United States This invention relates to a plastic cork and is more particularly concerned with plastic corks of the type commonly employed as a bung for insertion in the bung bushing of beer and ale barrels, casks or kegs and the like. This invention is an improvement over my prior Patent No. 2,657,817 dated November 3, 1953, entitled Plastic Bung for Beer Barrels or the Like.

.As set forth in my prior patent, above referred to, it has been found that plastic materials such as synthetic elastomers having the properties of polyethylene and vinyl derivatives are ideally suited for the formation of corks of the type referred to, being not only inexpensive as to manufacture but also non-absorbent, insoluble, indestructible and hence reusable. Such materials impart no taste to liquid of the receptacle and are inert as to liquids as well as gases. Some difiiculty, however, is experienced in the use of such corks since their elasticity is more restricted than rubber or cork wood. In my prior patent I provided a terminal shoulder at the inner end of the cork to engage the inner peripheral edge of the bung bushing within the barrel, cask or keg. The arrangement in that case was such that the shoulder of greater outside diameter than the internal diameter of the bung bushing opening was forced through the entire opening to expand against the inner shoulder of the bung opening upon the complete insertion of the cork. Such structure, while satisfactory and adequate, presented some difficulty in regard to ease of the original insertion and the necessary compression of the retaining shoulder during the entire movement of the cork through the bung opening to its final seated position. My prior bung, as well as those heretofore in common use, required insertion by heavy cumbersome, expensive, and time consuming equipment. The present invention seeks to overcome such difiiculties and provide a secure seal which may be inserted manually without use of any tools whatsoever. This is accomplished in the present construction by the provision of a reduced insertion end for the plastic cork, by the provision of tapering sealing surface and by a securing and retaining shoulder located adjacent the outer extremity of the cork. The shoulder is to be seated in and engaged by an undercut in the bung bushing. Since such bung bushings are frequently formed with a relieved or counter-bored internal diameter of greater dimension than that of either the entry port of the bung bushing or the inner terminus of the bushing opening, the invention does not necessarily contemplate a change in the bung bushing design.

It is therefore among the general objects of the present invention to provide a novel, simple and improved plastic cork having means to facilitate the ready insertion thereof and improved means for securing the cork against inadvertent outward displacement, as well as providing improved stable and secure sealing of the bung aperture. Numerous other objects, features and advantages of the present invention will be apparent from a consideration of the following specification taken in conjunction with the accompanying drawings in which:

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Figure 1 is a vertical sectional view of the cork of the present invention shown in location within the bung bushing of the present invention,

Figure 2 is a side elevation of the cork disclosed in Figure 1 before insertion.

Figure 3 is a vertical section similar to Figure 1 showing the cork inserted in a more conventional bung bushing, and

Figure 4 is a side elevation of the cork disclosed in Figure 3 in its compressed form.

In Figures 1 and 2, there is presented a bung hole bushing 10 permanently secured through the aperture 11 of a conventional barrel, keg or cask, fragmentarily indicated and bearing the numeral 12. The bung bushing 10 is of generally conventional cylindrical form having top and bottom radial shoulders 13 and 14 respectively. The bung bushing of Figure 1 is shown as with a central bore 15 which is relieved or undercut as at 16 to form an inwardly projecting shoulder 17 adjacent the outer end of the bore and within the general plane of the top shoulder 13. While the bore 15 above and below the tapering undercut 1 6 may be of uniform diameter either or both may be inwardly tapered toward the inner end of the bushing to enhance the seal of the port which is relieved or undercut as at 16 to form an inwardly projecting shoulder 17 adjacent the outer end of the bore and within the general plane of the top shoulder 13. While the bore 15 above and below the tapering undercut 16 may be of uniform diameter either or both may be inwardly tapered toward the inner end of the bushing to enhance the seal of the port by the plastic cork.

The cork of the present invention is generally indicated by the numeral 20 and is here shown of hollow construction not only in order to economize with respect to the material required and to form a light, easily manipulated cork, but the hollow characteristic lends resiliency and flexibility to the inner end of the cork so as to facilitate insertion. Another important characteristic of the hollow cork is that pressure within the container will tend to expand the walls against the sealing surfaces of the bung bushing thus the greater the internal pressure the greater will be the sealing force.

The internal surface 21 of the side walls 22 of the cork is shown as of generally uniform diameter throughout the length of the hollow opening of the cork. However, the internal cavity may be tapered if desired to add strength or facilitate manufacture. At the end of the outer side walls of the cork there is formed an inwardly tapering reduced diameter indicated at 23 so as to provide ease in insertion of the cork in the outer opening of the bung bushing and to guide the cork upon insertion into axial alignment with the bung opening. A frusto-conical intermediate wall 24 joins the reduced end 23 with the tapering outer side walls 25 of the body of the cork. At the opposite outer end the body of the plastic cork is reduced to form a head 26 above the shoulder 27. A transverse sealing end 28 is formed, closing the cylindrical wall and precluding outward passage of liquid or gases from the container. The outer surface 25 below the shoulder 27 tapers upwardly and outwardly from the top of the intermediate wall 24 to the transverse shoulder 27.

t will of course be understood that as the cork is inserted in the bung bushing, the reduced end 23 will permit ease of entry and will guide the cork in its movement into fully seated position within the bung bushing. As the cork is driven home the shoulder 27 is compressed as it passes the restriction of the bung port shoulder 17. When the sealing movement is completed, the cork shoulder 27 will expand behind the bung bushing shoulder 17 to be locked and permanently engaged, precluding any outward movement. In such sealed position both the head of the cork above the shoulder 27 and the lower tapered walls are compressed to permanently seal against inner walls of the bung bushing. It will of course be understood that when the barrel, keg or cask is emptied, the cork may be removed by further driving the cork through the bung bushing to be washed from the receptacle through the normal larger companion outlet.

In Figure 3 it will be seen that a hung bushing of a more conventional form, in which the central port is relieved as at '30 throughout an extended portion, may be sealed by the cork of the present invention. The enlarged diameter 30 is terminated at the top by an inwardly extending cork head receiving and sealing flange 31 and at the bottom its lower face forming a transverse lock surface 32. The inner flange 33 sealing engages the inner end of the cork.

With this form of bung bushing the same type of manual insertion is effective, the shoulder 27 is compressed past the shoulder 31 and thereafter expands to lock under the transverse surface 32. The cork head above the shoulder 27 will be sealingly compressed Within the shoulder 31 and the lower end of the tapered body will be sealingly compressed against the inner periphery of the shoulder 33. As noted in Figure 4, with this form of bung bushing the side walls 24 are free to expand in the undercut 30.

It will of course be understood that in the practice of the invention, numerous changes, modifications and the full use of equivalents may be resorted to without departure from the spirit or scope of the invention as outlined in the accompanying claim.

What I claim is:

The combination with a hung bushing for beer barrels or the like, defining a cylindrical passage characterized by a reduced outer uniformly cylindrical end bore of greater diameter, of a hollow yieldable plastic cork formed with a transversely closed uniformly cylindrical outer end of reduced external diameter to fit the reduced outer end bore of said bung bushing and an open ended externally tapered body forming an outwardly facing abrupt trans,- verse external shoulder at the junction of said tapered body and said reduced outer end whereby upon seating of said cork in said bushing, said reduced cork end will seat into said reduced bore end, cork shoulder will abut said bung bushing shoulder, whereby internal pressure within said hollow cork will retain said shoulder in contact and will expand said body outwardly towards the bore of greater diameter of said bushing.

References Cited in the file of this patent UNITED STATES PATENTS 33,964 Shaw Dec. 17, 1861 905,385 Swahn Dec. 1, 1908 1,962,409 Rasbridge June 12, 1934 2,657,817 Alvear Nov. 3, 1953 FOREIGN PATENTS 1,025,894 France Jan. 28, 1953 

